This invention relates to conveyors and more particularly to conveyors that have removable top plates that provide a continuous carrying surface and are capable of bending in both horizontal and vertical planes.
Poerink, U.S. Pat. No. 3,368,662 describes a conveyor belt comprising transverse rods having connecting links in the form of lamellas, thin plates, or wires. This conveyor is driven by dual spaced sprockets that engage the transverse rods.
Stuart et al., U.S. Pat. No. 3,094,206 shows several forms of conveyors. The form most pertinent to the present invention is shown in FIG. 11 and comprises a dual bend drive chain having U-shaped outwardly extending connecting links that mount horizontal and laterally extending support wires. The support wires form a noncontinuous conveying surface. As the conveyor is subjected to side bends, the spacing between the support wires is changed thereby limiting the minimum size of articles that can be carried without loss. Furthermore, the variation of spacing between the support wires of such a noncontinuous conveying surface renders it unsuitable for transporting tall cylindrical objects such as bottles.
Conveyors employing semi-circular meshing plate conveyor flights such as disclosed by U.S. Pat. Nos. to Dyson 2,157,283 and Davis 3,317,030 have serious limitations in that the articles conveyed must be centered on the flights to prevent spinning and upsetting of the articles when lateral bends are encountered.
Homeier et al., U.S. Pat. No. 3,651,924 discloses a conveyor chain having a continuous carrying surface that maintains a uniform, flat platform when the chain moves in either a straight line or a curved direction. The carrying platform is flexible and includes multiple, vertically oriented leaves telescopically mounted on transverse support rods that are carried on a central guide and drive chain. During bending movement of the conveyor, spacing between support rods varies; e.g., the spacing on the inside of the bend is smaller, and the spacing on the outside of the bend is progressively larger. The leaves being telescopically mounted with one another are effective to provide a continuous carrying surface and at the same time permit relative movement of the support rods. The disclosure and teaching of U.S. Pat. No. 3,651,924 are acknowledged and incorporated herein by reference.
While the noted references have provided partial solutions to the problems of transporting materials along a carrying surface, they are deficient in requiring a multiplicity of co-acting component parts that tend to excessive wear because of the constant sliding friction that occurs between and among rods, apertures, slots of leaves that provide a platform surface. Further, it is necessary to provide tabs, rounded corners, rivets, pins, and the like in order to achieve relatively trouble-free operation of the platform surface during movement of the conveyor as it is subjected to side bending forces. In addition, the telescoping action of the leaves causes variable spacing therebetween so that non-uniform interstices are formed in the carrying surface that fail to prevent smaller sized articles from falling through the chain.
All of these parts are of heavier construction and thereby reduce the payload which a conveyor may carry. Also, the multiplicity and complexity of the parts add greatly to the cost of the conveyor providing somewhat restricted application.